1. Field of the Invention
This invention relates to dry gas face seal units for sealing the space between a rotating shaft and a stationary housing against leakage of high-pressure gas. Such dry face seals are used in industrial compressors and gas or steam turbines at a wide range of operating pressures. The term "dry gas face seals" is defined as end face seals which are dry in that they do not use a liquid lubricant, but instead use the gas as a lubricant between the end faces of the seals. In particular, this invention relates to the construction of the stationary seal ring assembly.
2. Description of the Prior Art
Certain dry gas face seals use a stationary seal ring assembly which comprises a simple, unsupported carbon ring. This construction, however, allows for appreciable structural deformations and deflection in the ring when it is subjected to the pressure of the gas being sealed. Further, if a wide range of pressures is encountered, pressure balancing of the ring in the axial sense at all pressures is difficult. An example of this type of end face seal construction is disclosed in U.S. Pat. No. 4,212,475, issued Jul. 15, 1980, which is incorporated herein by reference. Accordingly, there is need for a stationary dry gas seal assembly that operates under the influence of pressure with little resulting load and structural deflection of the sealing ring. Further, this seal assembly must be axially balanced and must maintain axial pressure balancing integrity under a wide range of operating pressures.